CH04: Carbohydrates

Step 1

Salivary enzymes break down starch in the bread into smaller chains and the disaccharide maltose.

Which of the following statements regarding glucose absorption is true?

Glucose is absorbed mostly through the lining of the small intestine.

Fiber is not digested by the human digestive tract.

True

The acute condition of diverticulitis often requires a low fiber diet until the lining of the colon heals.

True

Carbohydrates contain carbon, hydrogen, and __________.

Oxygen

Insulin is produced in and released from the pancreas.

Pancreas

Step 3

Pancreatic amylase breaks down starch into the disaccharide maltose.

Glucose is stored as glycogen in the liver and in muscles.

Muscles

Animals store glucose polysaccharides in the form of glycogen.

Glycogen

Which of the following foods would be a good source of naturally occurring sugar?

Milk

The Dietary Guidelines recommended limiting added sugar in a diet. Which of the following foods would be considered a significant source of added sugar?

Nutri-Grain cereal bar

Which of the following is likely to be the most significant source of fiber in a cereal bar?

Rolled oats, cracked oats, steal cut oats

Plants store glucose as polysaccharides in the form of starch.

Starch

Sucrose is a type of simple carbohydrate composed of a glucose molecule and a fructose molecule.

Sucrose

Hormones That Have No Effecton Blood Glucose Levels

1. Cholecystokinin 2. Ghrelin

The body absorbs which form of digested carbohydrates?

Monosaccharides

Which of the following statements regarding fiber is TRUE?

Dietary fiber cannot be digested in the human digestive tract.

Disaccharides consist of two molecules of sugar joined together.

Disaccharides

Lactose, maltose, and sucrose are examples of this type of carbohydrate.

Disaccharides

Which of the following statements is CORRECT in regard to the role of insulin in blood glucose regulation?

All of these statements are correct.

Hormones That LowerBlood Glucose Levels

Insulin

How does the body respond to high blood glucose levels?

Insulin secretion

Which of the following statements is not true about carbohydrate digestion?

Disaccharides like sucrose do not need to be further broken down before being absorbed.

Insulin is a key hormone produced by the beta cells of the pancreas that plays a key role in regulating blood glucose levels after a meal.

Insulin

Step 2

Salivary amylase is inactivated by stomach acid.

Which of the following foods would be most helpful in preventing diverticulosis?

Whole grains, vegetables

Which of the following foods naturally contain(s) insoluble fibers that increase the bulk of digestive material and draw water into the large intestine, keeping the stools soft and moist?

Whole grains, cereals, and fruit

Rank the steps to indicate the effects of insulin to bring blood glucose levels to normal following a meal. Higher blood glucose levels to Normal blood glucose levels

1. Blood glucose levels rise following the digestion of a carbohydrate-rich meal. 2. Insulin is secreted from the pancreas into the bloodstream. 3. Insulin increases the number of glucose transporters on the cell membranes to allow the transport of glucose into the cells. 4. Insulin stimulates the liver to store excess glucose as glycogen and stimulates glycogenesis in the muscle cells. 5. Insulin stimulates lipogenesis in the adipose tissue.

Enzymes that are responsible for breakdown of disaccharides.

1. Sucrase 2. Lactase 3. Maltase

Carbohydrates provide __________ kcal of energy per gram.

4

Most dietary fiber passes through the digestive system without being digested and absorbed.

Fiber

Glucagon is a key hormone produced by the alpha cells of the pancreas that plays an important role in regulating blood glucose levels during times of fasting.

Glucagon

Step 4

Enzymes of the small intestine digest disaccharides into monosaccharides.

Foods only contain one type of carbohydrate.

False

It takes more than 8 hours for ingested carbohydrate to be digested, absorbed, and circulated in the cells.

False

Hormones That RaiseBlood Glucose Levels

1. Glucagon 2. Epinephrine 3. Norepinephrine

Disaccharides consist of __________ molecules of sugar joined together.

2

Which of the following nutrients is a carbohydrate?

All of these (fructose, high fructose, corn syrup, starch) are correct.

Glycogen is the storage form of glucose in the liver and muscles of humans and animals.

Glycogen

Complex carbohydrates are a category of nutrient compounds consisting of long chains of sugar molecules.

Complex carbohydrate

If there is no immediate demand for glucose, it is stored as __________.

Glycogen

What is the role of the hormone glucagon in regulating blood glucose?

Glucagon stimulates glycogenolysis, the breakdown of glycogen, to increase blood glucose concentrations.

Which of the following statements is correct?

Gluconeogenesis generates glucose from noncarbohydrate sources, such as amino acids, when blood glucose levels are low.

Glucose is the most abundant sugar molecule and the preferred source of energy for the brain.

Glucose

The body can either use glucose for energy, convert it to glycogen, or store it as fat.

Glucose

In response to insulin or glucagon, either glycogenesis or gluconeogenesis, respectively will take place in the liver.

Liver

Monosaccharides are a category of single sugar molecules that are absorbed easily in the small intestine.

Monosaccharides

Step 5

Some dietary fiber in the bread is fermented by bacteria; the rest passes through the large intestine to be eliminated.

Which of the following statements regarding absorption of monosaccharides is true?

Some monosaccharides are absorbed via a form of passive transport, namely facilitated diffusion.

What occurs when blood glucose levels rise following the ingestion of a glucose-rich meal?

The beta cells of the pancreas release insulin.

Rank the events in the sequence they follow from a lower blood glucose level to a normal blood glucose level. Lower blood glucose levels to Normal blood glucose levels

1. Blood glucose levels fall. 2. When blood glucose levels are low, glucagon is secreted from the pancreas into the bloodstream. 3. Glucagon targets the liver and stimulates glycogenolysis to release glucose into the bloodstream. 4. Gluconeogenesis in the liver is activated and converts amino acids and other noncarbohydrate sources to glucose, which is released into the bloodstream.

Fiber is a polysaccharide that gives plants their structure, and the bonds that hold the fiber molecules together are difficult to digest by the human body. Fiber plays an important role in a healthy diet by promoting healthy passage of stool and by helping to prevent many digestive and chronic diseases.

1. Fiber is important for adding bulk to stool and making it easier to eliminate stool as long as water intake is adequate. 2. Humans do not produce enzymes in the small intestine that can break down fiber. 3. Fermentation of fiber by gut bacteria results in production of certain molecules which can be used by cells of the large intestine for energy.

These are absorbed by the mucosal cells lining the small intestine and enter into the bloodstream.

1. Glucose 2. Fructose 3. Galactose

Enzymes that are responsible for breakdown of starches.

1. Salivary amylase 2. Pancreatic amylase

Simple carbohydrates are a category of sugars that contain either one or two molecules.

Simple carbohydrates

As part of the response to increased blood glucose after a meal, insulin triggers the number of glucose transporters on the cell membranes in the body to be increased.

Glucose transporters

Hypoglycemia occurs when blood glucose levels drop to lower-than-normal levels.

Hypoglycemia